1. Field of the Invention
The present invention relates to a novel silver- or silver-copper alloy-metal oxide composite material particularly suited to an electrode material for electric welding having a high durability against a loaded current with a large capacity, and a process of producing the same.
2. Description of Prior Art
Electric welding is widely used for assembly of various metallic plates for automobiles and electrical machinery and apparatus. The electric welding requires highly refractory electrodes, for which hard copper alloys such as Cr-Cu alloy are generally used. In particular, when a loaded current with a large capacity is applied as welding current, dispersion-strengthened materials, i.e., sintered materials produced by sintering a ceramic powder such as metal oxides or carbides together with copper, is used.
However, the above dispersion-strengthened materials exhibit insufficient welding resistance and wear resistance when subjected continuously to uses in which a welding current exceeding 10,000 A is applied, so that the life of the electrodes are quite short. Such a short electrode life will directly raise the production cost and lower efficiency of welding operations due to the necessity of frequent exchange of electrodes, which causes indirectly increase in production cost. Therefore, development of a material for electrodes with a long life is expected.